Modern electronic systems generally contain one or more devices that communicate with each other over a bus. For example, a computer generally comprises a processor or memory controller that communicates with a memory device over a bus to access programs and data contained in the memory device. The performance of modern electronic devices such as processors and memories continues to improve by operating the devices at higher clock speeds and/or widening the bus connecting the devices. Increasing clock speed and widening the bus, however, result in increased power consumption by the bus.